New type of optical fibre analogue SSB data communication system using edge‐emitting LED coupled to single‐mode optical fibre

摘要

This paper describes a single-mode(SM) optical fibre SSB data communication system for use in place of power-line data transmission. In the optical transmitter, SSB data is fed through the squarewave frequency (SWFM) modulator to the edge-emitting LED (ELED) module. The light beam of the ELED module is fed to the SM optical fibre having a length of 12km. In the optical receiver, the light beam received through the SM optical fibre is detected by the PIN photodiode module, and fed to the SWFM detector to obtain the double-pulse frequency modulation (DPFM) signal voltage. The DPFM signal voltage at the output of the SWFM detector is fed to the low-pass filter (LPF) to obtain analogue SSB data. When the transmission was experimentally carried out, the spurious component was as low as −50–−70 dB and the SNR of SSB data as high as more than 65–70 dB. The optical transmitter and receiver were attached to the conventional analogue SSB data communication system to constitute a new optical fibre analogue SSB data communication system. During the field test utilizing the new system, the crosstalk and SNR were 60–70 dB and 60–70 dB on each channel, respectively. Copyright © 1999 John Wiley & Sons, Ltd.